Mirror contact capacitor

ABSTRACT

A semiconductor structure and a method for fabricating the same. The semiconductor structure includes a substrate and a bonding layer in contact with a top surface of the substrate. At least one transistor contacts the bonding layer. The transistor includes at least one gate structure disposed on and in contact with a bottom surface of a semiconductor layer of the transistor. The semiconductor further includes a capacitor disposed adjacent to the transistor. The capacitor contacts the semiconductor layer of the transistor and extends down into the substrate. The method includes forming at least one transistor and then flipping the transistor. After the transistor has been flipped, the transistor is bonded to a new substrate. An initial substrate of the transistor is removed to expose a semiconductor layer. A capacitor is formed adjacent to the transistor and contacts with the semiconductor layer. A contact node is formed adjacent to the capacitor.

BACKGROUND OF THE INVENTION

The present invention generally relates to the field of semiconductors,and more particularly relates to trench capacitors.

Capacitors formed in three-dimensional trenches offer high capacitanceper unit area. Typical applications include the storage capacitor fordynamic random access memory (RAM), and for power supply decoupling inhigh-performance processors. In some instances, these capacitors areformed in the substrate of the semiconductor.

SUMMARY OF THE INVENTION

In one embodiment, a method for forming a semiconductor structure isprovided. The method comprises forming a transistor comprising at leasta first substrate, a semiconductor layer formed on the first substrate,a source/drain region, one or more gate structures, and at least onedevice isolation region. The transistor is then flipped. After flippingthe transistor, the transistor is bonded to a second substrate. At leastthe first substrate is then removed to exposed the semiconductor layer.A capacitor is formed adjacent to the flipped transistor and in contactwith the semiconductor layer. The capacitor extends down into the secondsubstrate. A contact node is formed adjacent to the capacitor andextends down into the second substrate.

In another embodiment, a semiconductor structure is provided. Thesemiconductor structure comprises at least a substrate, a bonding layer,one or more transistors, and a capacitor. The bonding layer contacts atop surface of the substrate. The transistor contacts the bonding layerand comprises at least one gate structure disposed on and in contactwith a bottom surface of a semiconductor layer of the transistor. Thecapacitor is disposed adjacent to the transistor and contacts thesemiconductor layer of the transistor. The capacitor extends down intothe substrate.

In a further embodiment, an integrated circuit is provided. Theintegrated circuit comprises a substrate, one or more transistors, abonding layer in contact with a top surface of the substrate, and atleast one capacitor. The transistor contacts the bonding layer andcomprises at least one gate structure disposed on and in contact with abottom surface of a semiconductor layer of the transistor. The capacitoris disposed adjacent to the transistor and contacts the semiconductorlayer of the transistor. The capacitor extends down into the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures where like reference numerals refer toidentical or functionally similar elements throughout the separateviews, and which together with the detailed description below areincorporated in and form part of the specification, serve to furtherillustrate various embodiments and to explain various principles andadvantages all in accordance with the present invention, in which:

FIG. 1 is a cross-sectional view of a fin field-effect-transistorutilizing an initial semiconductor structure according to one embodimentof the present invention;

FIG. 2 is a cross-sectional view of the initial semiconductor structureafter a dielectric layer has been formed thereon according to oneembodiment of the present invention;

FIG. 3 is a cross-sectional view of the semiconductor structure of FIG.2 after it has been rotated 180 degrees and bonded to a new handlesubstrate according to one embodiment of the present invention;

FIG. 4 is a cross-sectional view of the semiconductor structure of FIG.3 after a dielectric layer has been formed therein according to oneembodiment of the present invention;

FIG. 5 is a cross-sectional view of the semiconductor structure of FIG.4 after trenches have formed therein according to one embodiment of thepresent invention;

FIG. 6 is a cross-sectional view of the semiconductor structure of FIG.5 after a dielectric layer has been formed within one of the trenchesaccording to one embodiment of the present invention;

FIG. 7 is a cross-sectional view of the semiconductor structure of FIG.6 after a conductive material layer has been formed in both trenchesaccording to one embodiment of the present invention;

FIG. 8 is a cross-sectional view of the semiconductor structure of FIG.7 after contact trenches have been formed for the source/drain regionsand handle substrate according to one embodiment of the presentinvention;

FIG. 9 is a cross-sectional view of the semiconductor structure of FIG.8 after contacts have been formed in the contact trenches according toone embodiment of the present invention;

FIG. 10 is a cross-sectional view of decoupling capacitor structureaccording to one embodiment of the present invention; and

FIG. 11 is an operational flow diagram illustrating one process forforming a semiconductor structure comprising a trench capacitoraccording to one embodiment of the present invention.

DETAILED DESCRIPTION

It is to be understood that the present invention will be described interms of a given illustrative architecture; however, otherarchitectures, structures, substrate materials and process features andsteps may be varied within the scope of the present invention.

It will also be understood that when an element such as a layer, regionor substrate is referred to as being “on” or “over” another element, itcan be directly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” or “directly over” another element, there are no interveningelements present. It will also be understood that when an element isreferred to as being “connected” or “coupled” to another element, it canbe directly connected or coupled to the other element or interveningelements may be present. In contrast, when an element is referred to asbeing “directly connected” or “directly coupled” to another element,there are no intervening elements present.

The present embodiments may include a design for an integrated circuitchip, which may be created in a graphical computer programming language,and stored in a computer storage medium (such as a disk, tape, physicalhard drive, or virtual hard drive such as in a storage access network).If the designer does not fabricate chips or the photolithographic masksused to fabricate chips, the designer may transmit the resulting designby physical means (e.g., by providing a copy of the storage mediumstoring the design) or electronically (e.g., through the Internet) tosuch entities, directly or indirectly. The stored design is thenconverted into the appropriate format (e.g., GDSII) for the fabricationof photolithographic masks, which typically include multiple copies ofthe chip design in question that are to be formed on a wafer. Thephotolithographic masks are utilized to define areas of the wafer(and/or the layers thereon) to be etched or otherwise processed.

Methods as described herein may be used in the fabrication of integratedcircuit chips. The resulting integrated circuit chips can be distributedby the fabricator in raw wafer form (that is, as a single wafer that hasmultiple unpackaged chips), as a bare die, or in a packaged form. In thelatter case the chip is mounted in a single chip package (such as aplastic carrier, with leads that are affixed to a motherboard or otherhigher-level carrier) or in a multichip package (such as a ceramiccarrier that has either or both surface interconnections or buriedinterconnections). In any case, the chip is then integrated with otherchips, discrete circuit elements, and/or other signal processing devicesas part of either (a) an intermediate product, such as a motherboard, or(b) an end product. The end product can be any product that includesintegrated circuit chips, ranging from toys and other low-endapplications to advanced computer products having a display, a keyboardor other input device, and a central processor.

Reference in the specification to “one embodiment” or “an embodiment” ofthe present principles, as well as other variations thereof, means thata particular feature, structure, characteristic, and so forth describedin connection with the embodiment is included in at least one embodimentof the present principles. Thus, the appearances of the phrase “in oneembodiment” or “in an embodiment”, as well any other variations,appearing in various places throughout the specification are notnecessarily all referring to the same embodiment.

Referring now to the drawings in which like numerals represent the sameof similar elements, FIGS. 1-9 illustrate various processes forfabricating a semiconductor structure comprising a trench capacitor suchas a mirror contact embedded dynamic random-access memory (eDRAM). FIG.1 shows a cross-section of a semiconductor structure 100 (also referredto herein as the “first semiconductor structure 100”) at a startingpoint for embodiments of the present invention. For example, embodimentsof the present invention begin after a field-effect-transistor (FET) hasbeen fabricated and processed up through the front-end-of-the-line(FEOM) and a middle-of-line (MOL) stage, which includes forming of gateregions and a planarized dielectric layer. The semiconductor structure100 of FIG. 1 comprises a substrate 102; a dielectric layer 104 (e.g., aBOX layer or oxide layer) overlying the substrate 102; one or more finstructures 106 in contact with the dielectric layer 104; deviceisolation regions 108, 110 such as shallow trench isolation regions; andsource/drain regions (not shown in this cross-section).

The substrate 102 can be single crystalline and or a bulk substrate, asemiconductor-on-insulator (SOI) substrate, or a hybrid substrate. Insome embodiments, the substrate comprises at least one of Si, Ge alloys,SiGe, GaAs, InAs, InP, SiCGe, SiC, and other III/V or II/VI compoundsemiconductors. The dielectric layer 104, in one embodiment, is acrystalline or non-crystalline oxide, nitride, oxynitride, or any otherinsulating material. The dielectric layer 104, in one embodiment, is acrystalline or non-crystalline oxide, nitride, oxynitride, or any otherinsulating material. The fin structure(s) 106 comprises a semiconductormaterial such as silicon (Si). The substrate layer 102 and the finstructure(s) 106 can be made of the same or different materials.

In one embodiment, prior to forming the fin structures 106 thesemiconductor material/layer can be formed utilizing a layer transferprocess including a bonding step, or an implantation process such asSIMOX (Separation by IMplantation of OXygen). This semiconductor layercan be undoped or doped with either p-type or n-type dopants through ionimplantation, plasma doping, or gas phase doping. P-type transistors areproduced by doping the semiconductor layer 106 with elements from groupIII of the periodic table (e.g., boron, aluminum, gallium, or indium).As an example, the dopant can be boron in a concentration ranging from1×10E18 atoms/cm3 to 2×10E21 atoms/cm3. N-type transistors are producedby doping the semiconductor layer with elements from group V of theperiodic table (e.g., phosphorus, antimony, or arsenic).

Fins are formed, in one embodiment, by forming an etch-stop cappinglayer onto the semiconductor layer through, for example, deposition. Theetch-stop capping layer, in one embodiment, may be made ofsilicon-nitride although other material suitable in providing etch-stopfunction may be used as well. One or more fin structures aresubsequently formed or etched out of the semiconductor layer to be ontop of oxide layer 104 through a process involving masking, usingindustry-standard lithographic techniques, and directionally etching theetch-stop capping layer and underneath semiconductor layer. Thedirectional etching process, such as a reactive-ion-etching (RIE)process, stops on the dielectric layer 104. After the RIE etchingprocess, the photo-resist mask used in the lithographic etching processmay be removed, leaving the fin structure(s) 106.

FIG. 1 also shows that one or more gate structures/stacks 112, 114, 116are formed on and in contact with a top surface 118 of the fin structure106. The gate structures 112, 114, 116 each comprise a gate dielectric118 and a gate conductor 120. Gate spacers 122 surround and contact eachof the gate structures 112, 114, 116. A gate first or a replacementmetal gate (RMG) process can be used to form the gate structures 112,114, 116. It should be noted that although FIG. 1 shows a non-planarsemiconductor structure, embodiments are applicable to any type ofstructure such as planar FETs, vertical FETs, and/or the like.

FIG. 2 shows that a planarization dielectric layer 202 is deposited overthe fin(s) 106 including the gate structures and gate spacers, thesource and drain regions, and the STI regions. In one embodiment, theplanarization dielectric layer 202 is deposited by chemical vapordeposition or spin coating. For example, the planarization dielectriclayer planarization dielectric layer 202 can include doped or undopedsilicon oxide, silicon nitride, or a combination thereof. Theplanarization dielectric layer 202, in one embodiment, is formed as aself-planarizing layer, e.g., a spin-coated layer, or can be formed as anon-self-planarizing layer that is subsequently planarized., forexample, by chemical mechanical planarization (CMP). A planar topsurface of the planarization dielectric layer 202 is thus providedabove, or at the top surface of the gate structures 112, 114, 116. Inone embodiment, the planar topmost surface of the planarizationdielectric layer 202 includes silicon oxide.

The first semiconductor structure 100 is then flipped/rotated 180degrees, as shown in

FIG. 3. After rotation, the top layer 302 of the first semiconductorstructure 100 comprises the original substrate 102, and the bottom layer304 of the first semiconductor structure 100 comprises the dielectriclayer 202 and. Bonding adhesive/film is then deposited onto theplanarization dielectric layer 202 and/or to a new handle substrate. Thebottom layer 304 of the first semiconductor structure 100 is then bondedto the new handle substrate 402 to form a second semiconductor structure400, as shown in FIG. 4. The bonding adhesive/film 404, in oneembodiment, is spin applied at approximately 500 to approximately 3000rpm, soft-baked at between approximately 80° C. and approximately 120°C. and then cured at between approximately 300° C. and approximately350° C. for up to an hour in nitrogen. However, other temperatures andmethods for applying the adhesive/film 402 and bonding to the handlesubstrate 402 to the semiconductor structure 100 are applicable as well.The bonding adhesive 402 can be applied to the first semiconductorstructure 100, the new handle substrate 402, or both.

The handle substrate 402, in one embodiment, includes a semiconductormaterial, or a conductive material, or a combination thereof. Thethickness of the handle substrate 402 can be from 50 microns to 2 mm,although lesser and greater thicknesses can be employed as well. Thefirst semiconductor structure 100 can be flipped upside down before, orafter, being bonded to the handle substrate 402. In one embodiment, thehandle substrate 302 is heavily doped either with p-type dopant atoms orwith n-type dopant atoms to improve the capacitance and response of asubsequently formed capacitor. The dopant concentration of the handlesubstrate 402, in one embodiment, is from 1.0×10¹⁵/cm³ to 1.0×10¹⁹/cm³,although lesser and greater dopant concentrations are applicable aswell.

After the handle substrate 402 has been bonded to the firstsemiconductor structure 100, an etching, grinding, and/or polishingprocess(es) is performed to expose a bottom surface 502 of the fin(s)106, as shown in FIG. 5. For example, in an embodiment where thestructure 100 comprises a substrate 102 and a BOX layer 104, theoriginal substrate 102 and the BOX layer 104 are removed to expose thefin 106. Deep trenches 504, 506 are then formed. In one embodiment, thetrenches 504, 506 are formed by depositing a trench etch mask layer overand in contact with the STI regions 108, 110 and the substrate 102 ofthe first semiconductor structure 100. The trench etch mask layer isdeposited by, for example, chemical vapor deposition (CVD). The trenchetch mask layer, in one embodiment, includes doped or undoped siliconoxide, a dielectric metal oxide, a dielectric metal nitride, or a stackthereof. In one embodiment, the thickness of the trench etch mask layeris from 200 nm to 1,000 nm, although lesser and greater thicknesses canalso be employed. The trench etch mask layer is able to be formed as ablanket material layer having a same thickness throughout. The materialof the trench etch mask layer, in one embodiment, is selected to bedifferent from STI regions 108, 110 and the first substrate 102.

A photoresist layer is then applied over the trench etch mask layer, andlithographically patterned to form openings therein. The locations ofthe openings are selected to correspond to the locations of where thedeep trenches 504, 506 are to be subsequently formed through for acapacitor and a contact. For example, a first trench etch mask layer isformed over the semiconductor structure 100 in contact with thesubstrate 102 and is also formed over and in contact with the second STIregion 110. A second trench etch mask layer is formed for over and incontact with a first portion of the first STI region 108. The thirdtrench etch mask layer is formed over and in contact with a secondportion of the first STI region 108. This processes leaves unmasked atleast a first area of the structure 400 adjacent to the firstsemiconductor structure 100 for forming the first deep trench 506 and asecond area of structure 400 adjacent to the first area for forming thesecond deep trench 506. The pattern in the photoresist layer can betransferred into the trench etch mask layer by an anisotropic etch.

The pattern in the trench etch mask layer is transferred into thesemiconductor structure 400 by an anisotropic etch that employs thetrench etch mask layer as an etch mask resulting in formation of thetrenches 504, 506. The first trench 504, in which a capacitor will besubsequently formed, is formed through a first portion of the first STIregion 108 adjacent to the first semiconductor structure 100 andexposing at least a portion of the sidewall 508 of the fin 106. Thefirst trench 504 is further formed through the underlying planarizeddielectric layer 202, the underlying bonding film 404, and into thehandle substrate 402. The second trench 506, in which a contact node forthe handle substrate 404 will be subsequently formed, is formed adjacentto the first deep trench 506 through a second portion of the first STIregion 108, the underlying planarized dielectric layer 202, theunderlying bonding film 404, and into the handle substrate 402. In oneembodiment, trench depths from 5-20 micrometer are formed. However,other depths are applicable as well. The trench etch mask layer can beconsumed partially or completely during the anisotropic etch that formsthe first and second trenches 504, 506.

After the trenches 504, 506 have been formed, a dielectric layer 602 isformed within the first trench 504 conformally on and in contact withall physically exposed sidewalls and the bottom surface of the trench506. The dielectric layer 602, in one embodiment, is formed bydepositing a masking layer over the device and patterning the layer tohave an opening exposing the first trench 504. Alternatively, a maskingcan be formed only over the second trench. In yet another embodiment, nomasking layer is formed. A dielectric material is then deposited overthe structure and within at least the first trench 504. The dielectricmaterial can be deposited by methods known in the art including, forexample, chemical vapor deposition (CVD), physical vapor deposition(PVD), molecular beam deposition (MBD), pulsed laser deposition (PLD),liquid source misted chemical deposition (LSMCD), atomic layerdeposition (ALD), etc. The thickness of dielectric layer 602, in oneembodiment, is in a range from 3 nm to 12 nm, although lesser andgreater thicknesses can also be employed.

A disposable masking material such as a photoresist material is thenapplied into the first trench 504 after formation of the dielectricmaterial. The disposable masking material is recessed to a height belowthe top surface of the trench 504. The physically exposed portions ofthe dielectric material are selectively removed from above the recessedsurfaces of the disposable masking material and from within the secondtrench 506 if any dielectric material was deposited therein. Anyremaining masking material can be removed, for example, by ashing. Theresulting dielectric layer 602 comprises a top surface that is below thetop surface of the first trench 504 and above a bottom surface of thefin 106. In other embodiments, the top surface of the dielectric layer602 is below the bottom surface of the fin 106.

The dielectric layer 602 can include a dielectric metal oxide having adielectric constant greater than 8.0, which is commonly known in the artas a high dielectric constant (high-k) dielectric material. Additionallyor alternately, the dielectric layer 602 can include a dielectricsilicate of at least one metallic element. Examples of high-k materialsinclude but are not limited to metal oxides such as hafnium oxide,hafnium silicon oxide, hafnium silicon oxynitride, lanthanum oxide,lanthanum aluminum oxide, zirconium oxide, zirconium silicon oxide,zirconium silicon oxynitride, tantalum oxide, titanium oxide, bariumstrontium titanium oxide, barium titanium oxide, strontium titaniumoxide, yttrium oxide, aluminum oxide, lead scandium tantalum oxide, andlead zinc niobate.

A conductive material layer 702, 704 is deposited within each of thetrenches 504, 506 to completely fill the trenches 504, 506, as shown inFIG. 7. The conductive material layer 802 within the first trench 504 isdeposited on and in contact with the exposed portions of the dielectriclayer 602 within the first trench 504. The conductive material layer702, 704 includes a conductive material, which can be a metallicmaterial and/or a doped semiconductor material. The metallic material,in one embodiment, is an elemental metal such as tungsten, titanium,tantalum, copper, aluminum, or an alloy of at least two elementalmetals, or a conductive metallic nitride of at least one metal, or aconductive metallic oxide of at least one metal. The doped semiconductormaterial, in one embodiment, is a doped elemental semiconductormaterial, a doped compound semiconductor material, or an alloy thereof.However, other materials are applicable as well.

In one embodiment, the conductive material layer 702, 704 is depositedby physical vapor deposition (PVD), chemical vapor deposition (CVD),electroplating, electroless plating, or a combination thereof. Theconductive material layer 702, 704 is deposited to a thickness that issufficient to completely fill the first and second trenches 504, 506.The portions of the conductive material layer 702, 704 above ahorizontal plane including the top surface 502 of the fin 106 and a topsurface 706 of the STI regions 108, 110, in one embodiment, are removedby chemical mechanical planarization (CMP), a recess etch, or acombination thereof. In one embodiment, the remaining portions of theconductive material layer 702, 704 are present only below the horizontalplane including the top surface 502 of the fin 106 and a top surface 706of the STI regions 108, 110. It should be noted that the thermal cyclesassociated with the dielectric and node material fill processes areselected such that the transistors already in place are not adverselyaffected.

FIG. 8 shows that after the conductive layer 702, 704 is formed withinthe trenches 504, 506, a layer of dielectric material 802 is thenblanket deposited atop the entire structure 400. The blanket dielectric802 may be a silicon-based material, such as SiO2, Si3N4, SiOxNy, SiC,SiCO, SiCOH, and SiCH compounds; the above-mentioned silicon-basedmaterials with some or all of the Si replaced by Ge; carbon-dopedoxides; inorganic oxides; inorganic polymers; hybrid polymers; organicpolymers such as polyamides or SiLK™; other carbon-based materials;organo-inorganic materials such as spin-on glasses andsilsesquioxane-based materials; and diamond-like carbon (DLC, also knownas amorphous hydrogenated carbon, α-C:H). Additional choices for theblanket dielectric include any of the aforementioned materials in porousform, or in a form that changes during processing to or from beingporous and/or permeable to being non-porous and/or non-permeable.

The deposited dielectric 802 is then patterned and an etch is performedto form first and second contact openings (vias/trenches) 804, 806through the dielectric 802 and down into the fin 106 exposing a portionof the source/drain regions 810, 812. A third contact opening 808 isalso formed through the dielectric 802 and into the conductive layer 704of the second trench 506. A conformal contact liner material layer 902,904, 906 is formed within each of the trenches 804, 806, 808, as shownin FIG. 9. In one embodiment, the conformal contact liner material layer902, 904 contacts sidewalls 908, 910 of the exposed portions of the fin106 and also contacts exposed portions of the source/drain regions 810,812 within the first and second contact openings 804, 806. Within thethird contact opening 808, the conformal contact liner material layer906 contacts exposed sidewall portions 912 of the first STI region 108and exposed portions of the conductive layer 704. In one embodiment, thecontact liner layers 902, 904, 906 angle inwards from the top of the via804, 806, 808 to the bottom of the vias.

The contact liner material layers 902, 904, 906, in one embodiments,include a conductive material that reduces contact resistance betweencontact conductors subsequently formed and source/drain regions.Exemplary conductive materials that can be employed as the contact linermaterial layer include, but are not limited to NiPt, Co, NiAl, and W.The contact liner material layers 902, 904, 906, in one embodiment, areformed utilizing a conventional deposition process including CVD or ALD.The thickness of the contact liner material layers 902, 904, 906, in oneembodiment, is from 1 nm to 15 nm. However, other thicknesses areapplicable as well. In one embodiment, the bottom portions of thecontact liner material layer that are in contact with the source/drainregions 810, 812 react with the underlying material of the source/drainregions 810, 812 to form liner silicide portions 65. The liner silicideportions (not shown). The silicide portions reduce contact resistancebetween contact conductors subsequently formed and semiconductormaterials of the source/drain regions 810, 812.

After the contact liner material layer 902, 904, 906 has been formed,remaining volumes of the contact openings 804, 806, 808 are filled witha contact conductor material layer 914, 916, 918. The contact conductormaterial layer 914, 916, 918, in one embodiment, includes a metal suchas, for example, Cu, Al, W, Ti, Ta, or their alloys. The conductormaterial layer 914, 916, 918, in one embodiment, is formed by aconventional deposition process such as, for example, CVD, PVD, ALD, orplating. The contact conductor material layer 914, 916, 918 is depositedto a thickness so that a topmost surface of the contact conductormaterial layer 914, 916, 918 is located above or at the topmost surfaceof the contact level dielectric layer 902, 904, 906.

The blanker dielectric 802, portions of the contact liner material layer902, 904, 906, and portions of the contact conductor material layer 914,916, 918 that are located above the topmost surface of the contact linermaterial layer 902, 904, 906 are removed by employing a planarizationprocess, such as, for example, CMP. The resulting structure comprisessource/drain contacts 920, 922, a capacitor 924 such as an eDRAM cellcapacitor, and a bulk contact 926.

In other embodiments, similar processing techniques are performed toform a decoupling capacitor 1000, as shown in FIG. 10. In thisembodiment, the capacitor does not directly contact a finFEt as thecapacitor shown in FIG. 9. For example, FIG. 10 shows trenches 1002,1004 (similar to those of FIG. 5) formed through the STI layer 1006, theplanarization dielectric layer 1008, bonding film(s) 1010, and down intothe handle substrate 1012. A dielectric layer 1014 (similar to layer 602of FIG. 6) is formed in the first trench 1002, and a conductive materiallayer 1016, 1018 is subsequently formed within both trenches asdiscussed above with respect to FIG. 7. A conductive material layer1020, 1022 and a contact conductor material layer 1024, 1026 are thenformed within each trench 1002, 1004 similar to that discussed abovewith respect to FIG. 9. The capacitor 1000, in one embodiment, is thencoupled to an overlying wiring layer comprising, for example, a supplyrail 1028 and a ground rail 1030.

FIG. 11 is an operational flow diagram illustrating one process forforming a semiconductor structure comprising a trench capacitoraccording to one embodiment of the present invention. In FIG. 11, theoperational flow diagram begins at step 1102 and flows directly to step1104. It should be noted that each of the steps shown in FIG. 11 havebeen discussed above with respect to FIGS. 1-10. At least one transistoris formed, at step 1104. The transistor comprises at least a firstsubstrate, a semiconductor layer formed on the first substrate, asource/drain region, one or more gate structures, and at least onedevice isolation region. The transistor, at step 1106, isflipped/rotated.

After the transistor has been flipped, the transistor is bonded to asecond substrate, at step 1108. At least the first substrate is removed,at step 1110. The removal of the at least first substrate exposes thesemiconductor layer. A capacitor, a step 1112, is formed adjacent to thetransistor and in contact with the semiconductor layer. The capacitorextends down into the second substrate. A contact node, at step 1114, isformed adjacent to the capacitor. The contact node extends down into thesecond substrate. The control flow exits at step 1116.

Although specific embodiments of the invention have been disclosed,those having ordinary skill in the art will understand that changes canbe made to the specific embodiments without departing from the spiritand scope of the invention. The scope of the invention is not to berestricted to the specific embodiments, and it is intended that theappended claims cover any and all such applications, modifications, andembodiments within the scope of the present invention.

It should be noted that some features of the present invention may beused in one embodiment thereof without use of other features of thepresent invention. As such, the foregoing description should beconsidered as merely illustrative of the principles, teachings,examples, and exemplary embodiments of the present invention, and not alimitation thereof.

In addition, these embodiments are only examples of the manyadvantageous uses of the innovative teachings herein. In general,statements made in the specification of the present application do notnecessarily limit any of the various claimed inventions. Moreover, somestatements may apply to some inventive features but not to others.

What is claimed is:
 1. A method for fabricating a semiconductorstructure, the method comprising: forming a semiconductor structurecomprising at least a substrate, a bonding layer on and in contact withthe substrate, a dielectric region on and in contact with the bondinglayer, and a device isolation region on and in contact with the bondinglayer; forming a decoupling capacitor extending down from the deviceisolation region into the substrate; and forming a contact node adjacentto the and capacitor, the contact node extending down from the deviceisolation region into the substrate.
 2. The method of claim 1, whereinforming the decoupling capacitor comprises: forming a trench through thedevice isolation region and down into the substrate; forming adielectric layer within the trench; and depositing a conductive materialwithin the trench.
 3. The method of claim 1, wherein forming the contactnode comprises: forming a trench through the device isolation region anddown into the substrate; and depositing a conductive material within thesecond trench.
 4. The method of claim 1, further comprising: forming afirst contact trench within the decoupling capacitor; and forming asecond contact trench within the contact node.
 5. The method of claim 4,further comprising: forming a first contact liner on sidewalls of firstcontact trench; and forming a second contact liner on sidewalls of thesecond contact trench.
 6. The method of claim 5, further comprising:forming a contact conductor layer within each of the first trenchcontact trench and second contact trench after the first and secondcontact liners have been formed.
 7. The method of claim 1, furthercomprising: coupling the decoupling capacitor to a supply rail; andcoupling the contact node to a ground rail.
 8. The method of claim 1,further comprising: prior to forming the decoupling capacitor and thecontact node, forming one or more transistors comprising at least anadditional substrate, a semiconductor layer formed on the additionalsubstrate, a source/drain region, one or more gate structures, and adevice isolation region; flipping the transistor; after flipping thetransistor, bonding the transistor to the substrate; and removing atleast the additional substrate.
 9. A semiconductor structure comprisingat least: a substrate; a bonding layer in contact with the substrate; adielectric layer in contact with the bonding layer; a device isolationregion in contact with the bonding layer; and a decoupling capacitorextending down from the device isolation region into the substrate. 10.The semiconductor structure of claim 9, wherein the decoupling capacitorcomprises: a dielectric layer in contact with at least the substrate,bonding layer, and dielectric layer; and a conductive layer in contactwith at least the dielectric layer.
 11. The semiconductor structure ofclaim 10, wherein the decoupling capacitor further comprises: a contactlayer in contact with the conductive layer of the decoupling capacitor.12. The semiconductor structure of claim 11, wherein the decouplingcapacitor further comprises: a contact liner in contact with the contactlayer.
 13. The semiconductor structure of claim 9, further comprising: acontact node disposed adjacent to the decoupling capacitor, the contactnode extending down into the substrate, the contact node comprising aconductive layer.
 14. The semiconductor structure of claim 13, whereinthe contact node further comprises: a contact layer in contact with theconductive layer of the contact node.
 15. The semiconductor structure ofclaim 14, wherein the contact node further comprises: a contact liner incontact with the contact layer.
 16. An integrated circuit comprising:one or more semiconductor structures, wherein at least one semiconductorstructure comprises: a substrate; a bonding layer in contact with thesubstrate; a dielectric layer in contact with the bonding layer; adevice isolation region in contact with the bonding layer; and adecoupling capacitor extending down from the device isolation regioninto the substrate.
 17. The integrated circuit of claim 16, wherein thedecoupling capacitor comprises: a dielectric layer in contact with atleast the substrate, bonding layer, and dielectric layer; a conductivelayer in contact with at least the dielectric layer; a contact layer incontact with the conductive layer of the decoupling capacitor; and 18.The integrated circuit of claim 17, wherein the decoupling capacitorfurther comprises: a contact liner in contact with the contact layer.19. The integrated circuit of claim 16, wherein the at least onesemiconductor structure further comprises: a contact node disposedadjacent to the decoupling capacitor, the contact node extending downinto the substrate, the contact node comprising a conductive layer; anda contact layer in contact with the conductive layer of the contactnode.
 20. The integrated circuit of claim 20, wherein the contact nodefurther comprises: a contact liner in contact with the contact layer.